In the construction of submarines as well as surface ships, large aircraft and space craft (including space stations), it is frequently necessary to attach massive or awkward pieces of equipment permanently to complex, i.e., non-planar support structures: to attach lighter-weight equipment to complex surfaces in very tight quarters: or a combination of the two requirements, viz., attaching heavy equipment to complex support structures in confined spaces.
The problem is particularly acute in connection with the fabrication of large structures such as a space station while in earth orbit where it is compounded by such considerations as the need to conserve astronaut energy and to minimize the weight of tools and avoid the need for jigs and fixtures which would augment the load to be lifted into orbit. In any event, whether in space or on earth it is not always possible to maneuver sufficiently to attach retaining nuts to bolts extending from the complex- surface support through the equipment or object.
The invention capitalizes on the ability of certain metal alloys (hereinafter sometimes referred to as "shape-memory alloys" and described in detail) after having been conditioned to recall a particular dimensional configuration and then distorted from that configuration to revert to that configuration upon heating to above a critical (transition) temperature.
The basic general object of the invention to provide methods and apparatus for permanently joining structural components without the use of conventional fasteners of any sort.
A concomitant of this general object is the elimination of the possibility for parts mismatch, lost parts, jamming of parts, or loosening of the joined components due to vibration or other causes.
Another object of the invention is the provision of methods and apparatus for joining structural components which requires only a single active element and can be carried out by remote control.